Field of the Invention
The present invention relates to an image display apparatus and a control method thereof.
Description of the Related Art
A method normally used for changing a color of a display image (image displayed on a screen of an image display apparatus) is a method of changing a color of image data. If a pixel value of the image data is an RGB value (combination of an R value, a G value and a B value), the color of the pixel can be changed by changing the balance (ratio) of the R value, G value and B value. However, it is known that changing a color of image data drops the brightness of the image data and brightness of the display image.
A prior art concerning a liquid crystal display apparatus is a technique disclosed in Japanese Patent Application Laid-Open No. 2007-12534. According to the technique disclosed in Japanese Patent Application Laid-Open No. 2007-12534, if the color temperature of a display image is changed, the emission brightness of the backlight is adjusted using a correction value corresponding to the color temperature after the change, whereby the drop in brightness of the display image caused by the change of the color temperature can be suppressed.
However if a color of image data is changed, brightness of the image data drops, and as a result, the dynamic range of the image data drops. Then because of this drop in the dynamic range of the image data, contrast of the display image drops. According to the technique disclosed in Japanese Patent Application Laid-Open No. 2007-12534, the emission brightness of the backlight is adjusted using a same correction value, unless the color temperature is changed. Therefore according to the technique disclosed in Japanese Patent Application Laid-Open No. 2007-12534, the drop in contrast of the display image caused by the change of the color temperature cannot be suppressed, even if the drop in brightness of the display image caused by the change of the color temperature can be suppressed.